The suspected thieves are the Russian Carbanak gang, one of the world's most successful cybercrime outfits. After numerous hacks against banks extending back at least to 2015, experts estimate the group has stolen anywhere from several hundred million dollars to as much as $1 billion.

What: Point-of-sale vendors handle credit cards in stores around the U.S. They're hypervaulable targets for hackers looking for a big pay day.

Hackers targeted the company's servers and looked for passwords and credit card data, Fox-Brewster reported. It's not yet clear what was successfully stolen.